This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. ABSTRACT Autism is a complex developmental disability that appears during the first three years of life. It is commonly defined as a neurological or brain disorder that affects a persons ability to communicate, form relationships with others, and respond appropriately to the environment. Autism spectrum disorders (ASD) have been estimated to occur in as many as 1 in 150 individuals. They are four times more common in boys than in girls but show no greater occurrence in any racial, ethnic, or social group. There is now strong evidence from twin and family studies for the importance of genetic factors in the development of autism, although it is also clear that these influences are complex. It is possible that alterations in the DNA code itself contribute to autism, and it is also possible that other types of changes, known as epigenetic factors, influence the levels of protein activity without changing the DNA code itself. Genetic and epigenetic changes can be inherited or spontaneous. The goal of the Simons Simplex Collection (SSC) is to learn more about the molecular basis of autism and related disorders. To do this, the SSC is creating a resource of blood samples and clinical information that researchers can study as they search for connections between genes and specific behaviors. Data will be collected through a multisite network across North America, of which Baylor College of Medicine (BCM) is currently one of 13 sites. The SSC will gather the following information and materials from individuals who appear to be affected with ASD and their family members: (a) blood samples and (b) clinical data, including medical, diagnostic, and family history information. The purpose of behavioral, clinical and limited genetic evaluation is to fully characterize repository samples and provide data that will be necessary for comprehensive analysis of repository samples in the future. The SSC will store biomaterials at the Rutgers University Cell and DNA Repository (RUCDR) in New Jersey. The SSC will store de-identified clinical information in an encrypted, password-protected form in a central database run by The Simons Foundation. The SSC will make these de-identified biomaterials and clinical data available to qualified researchers who want to study autism and related disorders. Any use of these materials will first be reviewed and approved by the Simons Foundation.